High output mist producing unit



Sept. 8, 1970 F. E. COLGAN HIGH OUTPUT MIST PRODUCING UNIT 2Sheets-Sheet 1 Filed March 5, 1968 Spt. 8, 1970 F. a. COLGAN 3,527,411

HIGH OUTPUT MIST PRODUCING UNIT Filed March 5, 1968 2 Sheets-Sheet 2 f5v 54 A?! Patented Sept. 8, 1970 3,527,411 HIGH OUTPUT MIST PRODUCINGUNIT Francis E. Colgan, Midland Park, N.J., assignor to Auto ResearchCorporation, Boonton, N.J., a corporation of Delaware Filed Mar. 5,1968, Ser. No. 710,495 Int. Cl. A61m 11/06 U.S. Cl. 239-338 6 ClaimsABSTRACT OF THE DISCLOSURE Liquid is forced from a reservoir through anozzle that mixes it with air; and the liquid breaks up into dropletsthat become suspended in air in mist form; the mist moves directly intoan annular chamber surrounding the outlet of the nozzle; an extra airsupply is passed through the chamber in the vicinity of the nozzle; theextra air picks up additional mist particles which 'would otherwisesettle out, thereby increasing the mist output capacity of the mistproducing unit without having to unduly increase the size of the unit,in addition, the extra air supply increases the air pressure around themist nozzle outlet improving nozzle efficiency.

The present invention relates to mist prodcing units and, moreparticularly, to a mist producing unit which eificiently produces anincreased volume of mist by employing an extra air supply.

In some machinery installations, particular bearings and points must besupplied with lubricant which is in mist form, that is, with thelubricant broken up into droplets suspended in air, rather than inliquid form. These hearings or points may be inaccessible to liquidlubricant that is dripped or sprayed on them or they may be shaped sothat liquid lubricant would coat them non-uniformly. In order for themto be lubricated properly, they must be exposed to lubricant in mistform which surrounds the particular bearing or point. If necessary,means may he provided which uniformly condenses the mist lubricant ontothe hearing or point.

Mist is also used to cool bearings, points or surfaces. The liquid insuch mist may be water, lubricant or other spray cooling or lubricatingitem.

Liquid is placed in mist form by any of a number of known means. Forexample, a nozzle may be provided having a central passageway throughwhich liquid passes and an annular surrounding passageway through whichair under pressure is pumped. As the air exits from the nozzle, it drawsout the liquid by the Venturi effect and breaks up the liquid intodroplets of mist. The mist droplets are sufficiently small to be carriedby and suspended in the air. Some droplets formed are too large tobecome suspended in the air. They are blown against a collector wherethey coalesce and settle.

For a nozzle of particular design and dimensions, a predeterminedmaximum volume of air and of liquid per unit time can pass through thenozzle to create mist. Once the air passing through the nozzle becomessaturated with droplets of liquid, additional droplets are unable tobecome suspended in air. They strike each other and coalesce into largedroplets and are blown against the collector where they settle. If agreater volume of air per unit time contacts the droplets immediatelyafter they are broken up by passing through the nozzle, then it requiresa greater volume of droplets to saturate the air and a greater volume ofusable mist is formed per unit time. Accordingly it is desirable toincrease the air flow in the vicinity of the mist producing nozzle toincrease the volume of usable mist produced by a particular mistproducing unit in a predetermined period.

One manner of increasing air flow is to increase the size of the nozzle.But, a larger nozzle requires a larger size mist producing unit. Alarger nozzle is expelling more air at greater velocity. This createsturbulence at the nozzle exit. Without the larger mist producing unitbody, the mist droplets will be too confined, will be blown together andwill coalesce.

An alternate manner of increasing air flow is to place the air passingthrough the nozzle under greater pressure, which increases the velocityof air flow. Again, the greater velocity air flow creates moreturbulence and for a mist producing unit with this turbulence to operateefliciently and produce maximum mist, it must be made larger inside.

It is desirable to make a mist producing unit as small as possible,which also reduces its weight, expense of manufacture and difiiculty ofinstallation. To maximize air flow without increasing turbulence, anextra air supply, separate from the supply passing through the nozzle,mixes with the mist immediately after it is formed. This reduces thedroplet concentration in the air and causes more mist to be produced perunit time with a nozzle of predetermined size than is possible withother mist producing units.

In the present invention, the nozzle expels air and liquid, which formmist on mixing, toward a collector which collects the liquid dropletsthat cannot become suspended in air, The nozzle has a shielding devicesurrounding it to prevent the additional air being supplied from blowingacross the nozzle exit and preventing mist formation. The mist flowspast the end of the shielding device and into an annular chambersurrounding the shielding device. An air supply is directed into theannular chamber, and by appropriate bafiiing the air supply is directedannularly around the exterior of the shielding device. The newly formedmist moves into the additional air supply before the mist particles havea chance to coalesce and settle. A greater volume of mist per unit timeis produced.

The annular chamber has outlets leading to metering or apportioningunits adjacent each of the bearings, points or surfaces to be sprayed.There is a pressure drop between the annular chamber and the outletsfrom the meter units. Due to the pressure drop, the mist passes out ofthe annular chamber through a number of outlet conduits and is carriedto the bearings and points to be sprayed.

A mist producing nozzle operates most etliciently when the chamber intowhich the mist passes from the nozzle is at an air pressure which is ata predetermined ratio to the input pressure of the air moving into thenozzle. For example, for optimum mist production for a typical mistproducing nozzle, the air pressure at the outlet of the nozzle should beone half the air pressure at the nozzle input.

As was noted just above, the mist in the annular chamber moves throughthe mist metering or apportioning units. To properly apportion mistflow, these units each have a How restriction means therein. Necessarilyin restriction flow, the metering units will exert a back pressurethrough the conduits leading to the metering units, to the annularchamber and into the chamber formed by the shielding device around thenozzle outlet. The air pressure in the vicinity of the nozzle outletvaries in proportion to the back pressure exerted by the metering unitsand the outlet conduits leading to the metering units. The outletconduits are of suflicient diameter so that their effect upon the airpressure at the nozzle outlet is negligible. Therefore, only themetering units have a noticeable effect upon the back pressure.

It would be possible to choose and arrange the metering units so thattheir combined back pressure in the system would be the precise pressurethat should be present at the nozzle outlet. As a practical matter,however, this system is unworkable. Mist producing units of a particularsize must be uniformly manufactured. Each installation for a mistproducing unit will diifer in some respect, e.g., in the length ofconduits leading to the metering units, in the number of metering units,in the flow capacities of the various metering units, and so forthTherefore, it is very diflicult to design a mist producing unit whichwhen it is mounted in a system willhave a uniform predictable backpressure in the vicinity of the outlet of the nozzle. As a result, it isvery difiicultto obtain the necessary ratio between the input pressureto the nozzle and the pressure in the vicinity of the nozzle outlet byproviding metering units which are adjusted and chosen to provide thenecessary back pressure.

One other way of placing the input pressure to the nozzle and thepressure in the vicinity of the nozzle outlet in proper ratio is themethod used in the present invention. A separate air pressure source isprovided which increases the air pressure in the chamber in the vicinityof the output of the nozzle until this pressure is in proper ratio tothe input pressure at the maximum volume flow per unit time which thenozzle is capable of accepting to produce mist without undue turbulencein the mist producing unit. The extra air pressure source is thenadjusted so that the combined back pressure from the metering units andfrom the distribution system leading thereto, plus the pressure from theextra air pressure source and from the air leaving the nozzle outlet isin proper ratio to the input pressure in the nozzle when the nozzleinput pressure is set at the maximum level which the mist producing unitof predetermined size can tolerate without undue turbulence thereinwhich would force the mist droplets to bump into each other andcoalesce.

When the extra air supply is used, more mist can be provided with a mistproducing unit of predetermined size than can be produced by aconventional unit of the same size. This is because a conventional unitof the same size would have too much internal air turbulence if airpassed through it with sufficient rapidity to produce the amount of mista unit of the design of the invention produces. Hence, a mist producingunit in accordance with the invention can be as eificient as a largerconventional unit.

In view of the foregoing, the mist producing unit designed in accordancewith the present invention provides a number of benefits. First, theextra air supply picks up mist droplets before they have a chance tosettle and carries them into the distribution system, whereby a maximumvolume of mist is produced and a minimum of the mist produced is wasted.Also, the mist producing unit can be smaller than conventional units.Further, the extra air supply from a source of air under pressurecommunicates with the outlet from the mist producing nozzle, whereby theincrease in pressure in the chamber into which the nozzle empties placesthat chamber at a pressure which is in the proper ratio to the inputpressure to the nozzle, whereby the mist producing unit operates mostefficiently to produce a maximum volume of lubricant in a period oftime.

The volume of mist produced over time depends upon the volume of liquidlubricant passing to the mixing nozzle. One manner of controlling therate of this flow is to put a blocking element, such as an adjustableneedle valve in the path through which the liquid passes from a storagereservoir to the nozzle. The mist producing unit of the invention can beadapted with a novel means for controlling the liquid flow. The mistcreating mechanism draws liquid through a conduit from a reservoir thatis sealed both liquid and air tight. The mechanism is so positioned thatthe air exiting from both the nozzle and the extra air supply outletpasses into the space above the pool of liquid in the reservoir. Becauseof the back pressure and resistance to flow caused by the flowrestriction metering units, this elevates the air pressure within thereservoir, thereby pushing liquid into the conduit leading to thenozzle. At the same time, the air exiting from the nozzle exerts asuction on the liquid in the conduit that pulls the liquid out thenozzle. A bypass conduit connecting the air space in the reservoir withthe liquid conducting upstream of the entrance to the liquid conductingconduit and downstream of the nozzle will cause the nozzle suction todraw not only liquid through the nozzle, but also air under pressurefrom the reservoir. This reduces the flow of liquid volume per unit timeto the nozzle and reduces mist volume production. To vary the efiectupon liquid flow volume of the bypass conduit, an adjustable needlevalve is inserted in this conduit. The more this valve blocks theconduit, the greater the liquid flow rate and the mist production rate,and vice versa.

The above general description applies to any mist producing unit. Theliquid being converted into mist may be any liquid. The mist may be usedfor any purposes where mist is required, including lubrication, spraycooling, et al. The preferred use of the present invention is inconjunction with lubricant mist producing units. I

Accordingly, the primary object of the present invention is to provide ahigh output mist generating unit which maximizes the volume of mistproduced per unit time by a unit of predetermined size.

It is another object of the present invention to provide such a unitwhich minimizes the amount of liquid that first passes into mist formand then coalesces and condenses without passing as mist into the mistdistributing system.

It is a further object of the present invention to increase the mistproducing efliciency of the mist producing nozzle in a mist pro-ducingunit.

It is another object of the present invention to provide such a unitthat will be smaller in size than conventional units with the same mistvolume per unit time production capacity.

It is a further object of the present invention to provide means forcontrolling the mist production volume of a mist producing unit.

These and other objects of the present invention will become apparentwhen the following detailed description of the invention is read. Theinvention is described in conjunction with a mist producing lubricatorfor producing and distributing lubricant in mist form. Other materialsmay also be dispensed with a device designed in accordance with theinvention.

FIG. 1 is an elevation, partly in cross section, showing a lubricantmist producing unit designed in accordance with the teachings of theinvention;

FIG. 2 is a cross sectional plan view along the line and in thedirection of 22 of FIG. 1;

FIG. 3 is a cross section through the upper portion of the mistlubricator shown in FIG. 1, as viewed from the left of FIG. 1, showingthe operative elements of the lubricator;

FIG. 4 is a cross sectional plan View along the line and in thedirection 4-4 of'FIG. 3; and

FIG. 5 schematically illustrates a system making use of the lubricatorof the present invention.

Referring to FIG. 1, the lubricant mist producing unit 10 designed inaccordance with the present invention is comprised of an upper section12, shown in greater detail in FIG. 3, which is formed of a molded blockof material, such as metal, and having a plurality of bores and chambersprovided therein, as described hereinbelow. Depending from this upperportion is a reservoir 14 for containing liquid lubricant to be pumpedby the lubricator.

The lubricant exits from the lubricator in mist form because air ismixed with the liquid lubricant. Turning to FIG. 4, air under pressureis supplied through inlet 18 which has a screw threaded circumference orother means for receiving a coupling connection to the source of airpressure. A standard air pump or a standard shop air supply may beconnected to the air inlet 18. The air is pumped past branch conduit 24,which will be discussed below, through conduit 26 and into the annularchamber 28 of the nozzle 30.

Referring to FIG. 3, nozzle 30 tapers toward its exit 32, 38 and thechamber 28 similarly tapers and is of decreasing thickness toward theexit 32. The air exits from the nozzle 30 through air outlet 32 where itis mixed with the liquid lubricant, in a manner to be described to formlubricant mist in the chamber 34.

The air exiting through outlet 32, creates a Venturi effect by causingsuction at the outlet 38 of the central chamber 40 of the nozzle. Thisdraws any material in or above central chamber 40 of the nozzle throughsaid outlet.

The air pressure into nozzle 30 is set at the maximum level forpermitting mist to be formed in chamber 34 without undue turbulencebeing created which would cause the mist droplets to strike each otherand coalesce. The pressure in chamber 34 in the vicinity of nozzle exit32, 38 should be at a fixed ratio, e.g. 1:2, to the nozzle inputpressure. Pressure in chamber 34 will only be atmospheric pressureunless some means increases this pressure. The metering units to bedescribed, which apportion lubricant mist flow to various bearings andpoints to be lubricated, restrict free flow mist and exert a backpressure which increases the pressure in chamber 34. To further increasethis pressure, an extra air supply communicates, in a manner to bedescribed, with chamber 34 to bring the pressure therein up to therequired level.

As was noted above, there is lubricant in the reservoir 14. Due to thesuction at the nozzle outlet 38, lubricant is sucked out of reservoir 14through inlet 44a of pipe 44. Pipe 44 passes through hereinafterdescribed annular chamber 126 and through sealing gasket 48 which sealsthe aforementioned chamber at the point where pipe 44 exits from it.

Pipe 44 leads to filter 46 which may be any standard filter known in theart, including but not limited to a felt pad, wire mesh, a wire woolscreen, a porous sintered metal disc or other porous element, and whichfilters impurities and dirt from the lubricant without halting its flow.Screw 50 is above filter 46 and is removable to permit access to filter46 when the filter is to be serviced or replaced.

O-ring 49 surrounds screw 50 and prevents lubricant from leaking pastthe sides of filter 46. All lubricant passes through filter 46 intochamber 51.

From chamber 51, lubricant exits through conduit 52 into annular chamber52a around screw 50, and from there the lubricant passes into conduit 53which leads to junction 54 which has drip faucets 56 and 58 (FIG. 1)thereto connected. Referring to FIGS. 1 and 3, lubricant passing throughfaucets 56, 58 drips into the chamber 60. Chamber 60 is enclosed on allsides but one by the solid material of which the upper portion 12 of thelubricator is comprised. On its outward facing side, chamber 60 isenclosed by a transparent window 62, comprised of glass or clearcorrosion-resistant plastic, which is secured liquid tight around itsperiphery by a frame 64, which is in turn sealed liquid tight with thebody portion 12 of the lubricator. Through window 62, the drops fallingfrom faucets 56, 58 may be observed. For an example of a faucet andwindow combination, see US. Pat. No. 3,076,526, entitled Lubrication,issued Feb. 5, 1963 to Thomas R. Thomas, and assigned to the assigneehereof. If the drops are falling too fast, this may be reduced byreducing the flow of liquid lubricant up pipe 44; and if the drops arefalling too slowly, the flow of liquid lubricant may be increased. Theliquid flow rate adjustment is accomplished by means to be described. Byobserving that lubricant is properly dripping from nozzles 56, 58, andobserver will know that the lubricator is properly operating. If thenozzles 56, 58 cease to drip, then an observer would know that thelubricator should be checked for malfunction.

The liquid lubricant dripping through chamber 60 is sucked by the airflow into the nozzle liquid inlet 66, through the nozzle chamber 40, andout nozzle liquid inlet 38. When the outrushing air and liquid lubricantmix, the liquid lubricant is broken up into droplets, many of which areof minute size. The smaller droplets are light enough to becomesuspended and to float in the air exiting from air outlet 32. The nozzleoutlet 32, 38 has a cylindrical shield 33 around it which extends ashort distance away from the nozzle in the direction in which air isblown out of nozzle 30. The mist must pass the end of shield 33. Shield33 is provided to protect the exit of nozzle 30 from crosswinds of airfrom an extra air supply, to be described. The crosswinds would deflectthe air exiting from exit 32 and might thereby disturb the suction onchamber 40; and they might blow the newly formed lubricant droplets intoeach other just after they were formed near nozzle liquid outlet 38 andbefore they had the opportunity to disperse in the air blowing out ofair outlet 32 and circulating within the confines of shield 33. Shield33 should be as short as possible to minimize the distance the dropletsformed at nozzle 30 must travel before they are picked up by the airflowing through chamber 126, as is described below. In addition, theexterior of shield 33 serves as one side of the annular chamber 126, tobe described below, to cooperate in the directing of air coming from anadditional air supply to be described below, through the annularchamber.

Shield 33 is illustrated as being cylindrical with a circular crosssection. However, the particular cross-sectional shape of the shield isnot critical so long as it will perform the desired functions describedherein. Shield 33 has a narrowed exterior diameter upper section 35which is threaded on its exterior to matingly engage a threaded aperturein upper lubricator section 12.

Connecting panels 36 on shield 33 join it to element 72. Element 72 hasa dual function. First, a number of the droplets formed as the air andliquid lubricant mix are too heavy to float in or be supported by theair in chamber 34. They fall or are blown by the air rushing out of airexit 32 against the surface 74 of element 72. The surface 74 is domeshaped so that wherever these droplets settle they roll downward andoutward. Between adjacent panels 36 are located openings 78 which alsoserve a dual function. Only one of these is now described. Surface 74extends through each opening 78 and comprises the base thereof. Thepanels 36 between adjacent openings 78 are so curved as to cause liquidlubricant rolling toward the edge of surface 74 to pass through theopenings 78. Lubricant in liquid form rolling off the edges of surface74 settles back into the pool of lubricant within reservoir 14.

Element 72 may perform a second function, holding the reservoir 14 inplace. The reservoir 14 is formed as an open top container. Cap 80 formsthe base of reservoir 14 and also supports cylindrical wall 82. Theupper edge of wall 82 fits into an annular notch 84 on the bottom oflubricator portion 12. A resilient annular gasket 86 or other sealingmeans is provided for affording an air tight seal thereby preventingleakage of air and mist. Cap 80 is pressed by a means to be describedagainst an annular gasket 90. This seals base cap 80 against the lowerend of chamber wall 82 for providing an air and liquid tight seal tocompletely enclose the reservoir 14.

Element 72 has a threaded aperture 92 therein for receiving the matinglythreaded first end of reservoir support post 94. Post 94 is threaded at96 at its other end for receiving a cap securing nut 98. After post 94has been inserted in element 72, and reservoir 14 and base plate 80 havebeen positioned, the threaded cap nut 98 is screwed over the threadedend 96 of post 94 which presses on cap 7 80. The reservoir 14 is sealedclosed around post 94 by gasket 99.

Post 94 has an opening 102 at its base which is connected to an outletchamber 103. This permits draining of the reservoir and removal of anyimpurities which have settled in the pool of lubricant within thereservoir. Exit port 104 communicates with chamber 103 and is secured toscrew cap 106 which can be rotated to rotate the port element 107 toopen or close port 104.

The openings 78 are at the outward end of shield 34. Herein is found thesecond function of openings 78. They are large enough in size and panels36 between adjacent openings 78 are correspondingly small enough thatlubricant mist floating within chamber 34 drifts and is blown by the aircontinually exiting from nozzle exit 32 through openings 78.

As discussed above, the present invention makes use of an extra airsupply which both picks up mist droplets before they coalesce and settleand increases the air pressure in the reservoir to place this pressureat a proper ratio with respect to the input pressure passing throughconduit 26 to the nozzle inlet. Turning to FIG. 4, air entering inlet 18passes not only through conduit 26 but also enters conduit 24, which isthe start of an extra air supply. In conduit 24, the air strikes thetapered end 108 of a needle valve 110. Valve 110 has a forward exteriorsurface 112 which slidingly engages the walls of the bore within whichthe valve is positioned in an airtight fashion. Airtight engagement isenhanced by O-ring 113. The rearward end 114 of the valve 110 isthreaded to matingly engage a threaded portion of the bore within whichthe needle valve is positioned.

Valve 110 has a notched head 116 which may be rotated by, for example, ascrew driver to move the needle valve in and out of its bore. When theneedle valve is moved to be fully inserted, it covers the inlet opening120. When the needle valve is withdrawn, it exposes opening 120 to theair moving into conduit 24. Adjustment of the needle valve tointermediate positions between the two extremes just describedapportions a greater or smaller part of the air passing through theinlet 18 to the opening 120, as opposed to the conduit 26. The presentinvention has been illustrated using a small air supply that is dividedbetween two conduits. It is within the contemplation of the invention tocause air to flow along two pathways by any means, e.g. providing twoair supplies.

Turning to FIG. 1, the opening 120 of the extra air supply is connectedby a conduit 122 with the annular chamber 126, which is described ingreater detail below.

Conduit 122 directs the air exiting therefrom in substantially the samedirection as the direction of flow out of nozzle 30. Returning to FIG.3, chamber 126 is annular and is enclosed by lubricator section 12 onall but its bottom side, the side communicating with reservoir 14.Shield 33 forms the interior wall of chamber 126. The air passing underpressure through conduit 122 into the upper side of chamber 126 wouldnormally flow down into the reservoir 14 and against the surface of thelubricant therein.

Referring to FIGS. 1 and 2, an arcuate bafile plate 130 is positioned tosubstantially cover the entire open bottom of the chamber 126 over anarcuate portion of the bottom of said chamber. The baffle plate iscentered beneath the outlet from conduit 122. On its interior edge thebaffle plate is supported by its tab 132 that is seated between ashoulder of lubricator portion 12 and a shoulder on the exterior ofshield 33. On its exterior edge, baffle plate 130 may reach to a support134 or only partway across chamber 126, so long as it extends acrosschamber 126 far enough to redirect the flow of the extra air supply aswill be described. The inrushing air strikes the surface of the bafileplate 130 and is redirected transversely to its downward direction. Itis desirable to have the redirected air move in one direction. Thus, thebaffle plate, in addition to being inclined downward toward its outeredge, is also inclined from one arcuate end to the opposite arcuate endthereof. The continuing flow of air through conduit 122 forces theredirected air to flow in a continuous transverse or sideways stream.

Baffle plate does not extend completely around the exterior of shield33. The redirected airflow therefore sweeps around shield 33 at a heightlower than that of baffle 130 whereby the air sweeps past the openings78, which are largely below bafile 130, to carry away the mist.

Considering FIGS. 1 and 3, the redirected air passes through the annularchamber 126 and comes into contact with the openings 78. As mist ismoved, by air exiting from exit 32, from within chamber 34, it is mixedwith the air moving through chamber 126. The concentration of liquiddroplets in the mist immediately decreases due to the increase in thevolume of air supporting the droplets.

A given volume of air can'only support a predetermined volume oflubricant droplets. Once the air is saturated, additional droplets, nomatter how fine or minute, strike each other, coalesce and condense out.Increase the volume of air, and the volume of lubricant droplets thatcan be supported also increases. Therefore, the use of annular chamber126 to provide an extra air supply for picking up the lubricant mistdroplets immediately after they are formed in and pass from withinshield 33 permits a lubricant mist forming unit, with a nozzle that canonly produce a predetermined amount of mist per unit time, to produce agreater volume of usable mist within that predetermined period. Inaddition, the extra air supply permits a lubricator adapted with it tobe made smaller in size without any turbulence problems that would occurin a normal lubricator of that size producing as much mist.

The longer the distance the mist produced by nozzle 30 must travelbefore contacting the extra air supply, the greater the volume oflubricant droplets that will coalesce and settle out. Thus, it ispreferable as is done in the present invention, to bring the extra airsupply as close to the nozzle exit as possible by making shield 33short.

As has been discussed, the extra air passing out of conduit 122increases the pressure in chamber 126. Chamber 126 opens into reservoir14 above the pool of lubricant therein. Reservoir 14 is sealed and theincreased pressure cannot escape. The chambers 126, 34 and reservoir 14together form an airtight sealed container with all these elements beingin communication with the container. The metering units, to bedescribed, restrict the exit of pressure from the system. As thepressure in chamber 126 and in reservoir 14 increases, since chamber 34communicates with them, the pressure therein adjacent the outlet ofnozzle also increases, until the optimum pressure level, previouslydescribed, is reached. The mist laden air in annular chamber 126 passesthrough a plurality of outlet ports 131 which are spaced about thechamber 126. The outlet ports 131 connect with main distribution line166 (FIG. 5) which leads to the mist distributing system. Thedistributing system schematically illustrated in FIG. 5 is exemplary ofthe infinite variety of such systems. The mist passes from lubricator 10through conduit 166 and through junction 168. Some of the lubricant mistpasses through conduit 170, and through a metering unit 172 thatapportions the volume of mist that passes through conduit 170, tolubricate the bearing 174. The bulk of the mist passes through junction168 to conduit 176 and then to junction 178 where a portion of thelubricant mist passes down conduit 180 to metering unit 182. Meteringunit 182 may be a mist condensation fitting which condenses the mist toa liquid form to lubricate the bearing 184. Mist passes through conduit186 to metering unit 188 which apportions per unit time the volume oflubricant passing to bearing or point 190.

As mist or lubricant is forced out of metering units 172, 182 and 188,there is a pressure drop across each of them, which creates a pressuredrop in distribution line 166. The reduced pressure in line 166 issensed within annular chamber 126 and the lubricant mist in said chamberis drawn into line 166 and is drawn through the metering units by thepressure drop over the metering units.

Each of the metering units has a bore extending completely therethroughwith a flow restriction means therein, e.g. a portion of the bore isnarrowed. The restriction limits the rate of flow through the unit. Inrestricting flow, each metering unit exerts a back pressure which istransmitted through conduit 166 back into chamber 126. This backpressure, plus the pressure added to it by the infiowing extra airsupply, elevates the pressure in chamber 34 to the required level foroptimum operation of nozzle 30.

Referring to FIG. 3, reservoir filler cap 134 is provided which has ascrew threaded exterior 136 that mates with a cooperatingly threadedaperture within the portion 12 of the lubricator. The filler capcommunicates with an aperture 138 that leads to the chamber 126.Lubricant poured into conduit 138 falls into the reservoir 14. Otherlocations for the filler conduit and filler cap 134 may be chosen topermit lubricant to enter the reservoir 14.

There has just been described a novel lubricant mist producinglubricator for producing a greater volume of usable mist per unit timewith a nozzle of predetermined mist producing capacity than the volumeof mist that can be produced with prior art mist producing units. Thelubricator can be smaller in size than a conventional lubricator forproducing the same volume of mist since with the present invention,there is less air turbulence within the mist producing unit, whereby themist particles produced will not be striking each other, coalescing andsettling.

In the event that it is desired to vary the volume of liquid lubricantmoving to the nozzle portion 40, valve means known in the art, such asan adjustable needle valve, may be placed anywhere along pipe 44 orconduit 53 and may be made adjustable, e.g. by being screw threaded withthe screw being accessible from the exterior of the lubricator.

A preferred means for controlling the volume of liquid lubricant passinginto the system is shown in FIGS. 1 and 4. As was noted above, the airpassing out air outlet 32 of nozzle 30 creates a suction force whichpulls lubricant up pipe 44 and through connecting conduits out liquidoutlet 38. In addition, chamber 126 has an open bottom whichcommunicates with reservoir 14, and the air passing into said chamberfrom conduit 122 increases the air pressure within the airtightreservoir 14 because of the back pressure caused by the metering units.This pressure increase cooperates with the escaping air from nozzle 32,which also increases the air pressure in reservoir 14, to press theliquid lubricant in reservoir 14 down, which, in turn, forces same uppipe 44. The present lubricant mist production volume controller makesuse of the knowledge that if the air pressure in reservoir 14 isconnected to the liquid lubricant flow path downstream of the inlet 44aof pipe 44 and upstream of the nozzle 30, some of the air under pressurewithin reservoir 14 will be sucked along with lubricant into thelubricant flow conduit system 44, 46, 52, 52a, 53, 56, 58 by the suctionexerted by air flow through nozzle 30. If the opening in the lubricantflow conduit system to the air under pressure within reservoir 14becomes sufiiciently enlarged, the suction force exerted by the airexiting through outlet 28 of the nozzle will only draw air out ofreservoir 14 and no liquid lubricant will be pumped. As the width of theopening connecting the liquid lubricant flow system with the air underpressure in reservoir 14 is reduced, there is insuflicient air beingsucked out of reservoir 14 to satisfy the suction exerted by nozzle 30and liquid lubricant will again flow out of reservoir 14 up pipe 44.

In FIG. 1, note the pipe 140 which opens at its end 142 into chamber126, which is in communication with reservoir 14 and which is connectedat its end 144 into lubricant flow conduit 53. Were pipe unobstructed,the suction due to the passage of air through nozzle exit 32, plus theincrease in pressure within reservoir 14 would drive the air underpressure within reservoir 14 up along pipe 140 and into conduit 53,there to pass down and through nozzle exit 38, whereby no liquidlubricant would pass through the faucets 56, 58 and out nozzle 30.Turning to FIG. 4, to preclude this possibility, a needle valve isprovided, having a tapered front end 152 for blocking pipe or conduit140. Needle valve 150 has a stem 154 which engages the surface 156 ofthe wall around a bore through the body portion 12 of the lubricator.The engagement is airtight and O-ring further ensures this. The valvehas a screw threaded end 158 which mates with a cooperatingly threadedaperture within the body portion 12 of the lubricator. At the exteriorend of the valve stem 154 is a notched head 160 which may be operated bya screw driver to rotate the valve stem, thereby to move tapered valveelement 152 in or out of the path of flow of conduit 140. When valve 150is moved inwardly, it blocks conduit 140, thereby eliminating the bypassof pressure out of reservoir 14, thereby increasing the quantity ofliquid lubricant passing up pipe 44. Similarly, movement of valveelement 152 out of the conduit 140 permits a greater pressure flowthrough conduit 140, thereby reducing the flow through pipe 44 andreducing the liquid flow out of nozzle 30.

The invention of a novel mist producing unit has been illustrated with amist lubricator. However, any other liquid material may be used inconjunction with the invention and the invention may be used for otherpurposes besides lubrication, e.g. spray cooling.

There has just been described a mist producing unit which is enabled toprovide a greater volume of lubricant mist per unit time with a nozzlehaving predetermined mist producing capacity than is possible with mistproducing units of the prior art. This is accomplished by providing anadditional air supply which sweeps past the mist just after it flows outof the mist creating nozzle, thereby decreasing the concentration oflubricant droplets within the mist. With such an apparatus, less spaceis needed within the mist producing unit for forming mist efiicientlysince the apparatus reduces the amount of air turbulence which wouldnormally occur within a mist producing unit producing as much mistefficiently. As an additional feature, the present invention includes apressure bypass which cycles some of the pressure in the reservoir thatis caused by the outflow of air from the nozzle and the extra air supplyback into the liquid suction line, thereby varying the rate of liquidflow up said line.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now be apparent tothose skilled in the art. Therefore, this invention is to be limited,not by the specific disclosure herein, but only by the appended claims.

What is claimed is:

1. In a mist producing unit,

a nozzle for mixing air and liquid for forming mist, said nozzle havingan inlet means into which liquid and air pass to enter said nozzle andan outlet means out of which liquid and air are forced in a firstdirection to mix and to form mist;

a liquid conduit means connected to said inlet means for transmittingliquid from a reservoir to said nozzle;

a first air supply conduit means connected to said inlet means fortransmitting air under pressure from an air supply to said nozzle;

a mist receiving and dispensing installation comprising at least onemist flow volume metering unit to be positioned to apportion flow volumeto an item to be serviced with mist, and a conduit connecting said atleast one metering unit with said exit means, whereby the restriction toflow caused by said at least one metering unit creates a back pressurein said conduit for operating upon said nozzle outlet means;

the improvement comprising,

a second air supply means including a conduit means for transmitting airunder pressure from an air supply and including means for directing theadditional air into the vicinity of said nozzle outlet means therebyenabling the additional air to mix with the mist exiting from saidnozzle outlet means which increases the available air for supportingmist droplets and increases the volume of mist produced by said unitwithout increasing the air turbulence within said unit so that said unitmay be kept smaller in size;

an exit means for ronducting the mist now mixed with additional air to amist receiving installation;

an airtight container communicating with both said outlet means of saidnozzle and said second air supply conduit means; said exit meanscommunicating with said container;

said container including a reservoir for containing liquid to beconverted to mist, whereby the increase in the air pressure within saidcontainers due to air being expelled both by said outlet means of saidnozzle and by said second air supply means, cooperating with the flowrestriction effect of said metering units, increases the air pressurewithin said reservoir;

said liquid conduit means comprising a pipe means having an inletextending into said reservoir for drawing liquid through said inlet andthrough said pipe means out from within said reservoir;

a pressure bypass conduit communicating between said container and saidliquid conduit means at a position downstream of said inlet to saidliquid conduit means and upstream of said nozzle inlet means, fortransmitting pressure in said container into said liquid conduit means;

and valve means in said pressure bypass conduit for controlling thepressure transmitted by said bypass conduit.

2. In a mist producing unit,

a nozzle for mixing air and liquid for forming mist; said nozzle havingan inlet means into which liquid and air pass to enter said nozzle andan outlet means out of which liquid and air are forced in a firstdirection to mix and to form mist;

a liquid conduit means connected to said inlet means for transmittingliquid from a reservoir to said nozzle;

a first air supply conduit means connected to said inlet means fortransmitting air under pressure from an air supply to said nozzle;

the improvement comprising,

a second air supply means including a conduit means for transmitting airunder pressure from an air supply and including means for directing theadditional air into the vicinity of said nozzle outlet means therebyenabling the additional air to mix with the mist exiting from saidnozzle outlet means which increases the available air for supportingmist droplets and increases the volume of mist produced by said unitWithout increasing the air turbulence within said unit so that said unitmay be kept smaller in size;

an exit means for conducting the mist now mixed with additional air to amist receiving installation;

a shielding device around the periphery of said nozzle outlet means ofsaid nozzle for shielding said exit from an additional air supply; saidshielding device extending a predetermined distance in said firstdirection so as not to interfere with the mixing of an additional airsupply with the mist passing beyond said predetermined distance;

said second air supply means including means for directing theadditional air around the exterior of said shielding device,'therebyenabling the additional air to mix with the mist passing beyond saidshielding device.

3. In the mist producing unit of claim 2, the improvement furthercomprising, said means for directing air including a chamber around saidshielding device formed by the exterior of said shielding device and awall spaced away from said shielding device; said second air supplyconduit means having an outlet communicating with said chamber.

4. In the mist producing unit of claim 3, the improvement furthercomprising, said outlet of said second air supply-means being aimed soas to direct the air exiting therefrom substantially in said firstdirection; a first air directing bafile within said chamber forredirecting the air from said outlet to pass around said shieldingdevice and to pass through said chamber transversely to said firstdirection; said first baffle extending transversely of said firstdirection around a portion of said chamber. 7

5. In the mist producing unit of claim 4, a collector disposed andsupported in spaced opposed relationship to said outlet means from saidnozzle, in order that the liquid droplets which are not suspended in airmay strike said collector and condense into liquid form.

6. In a mist producing unit,

a nozzle for mixing air and liquid for forming mist; said nozzle havingan inlet means into which liquid and air pass to enter said nozzle andan outlet means out of which liquid and air are forced in a firstdirection to mix and to form mist;

a liquid conduit means connected to said inlet means for transmittingliquid from a reservoir to said nozzle;

a first air supply conduit means connected to said inlet means fortransmitting air under pressure from an air supply to said nozzle;

the improvement comprising,

a second air supply means including a conduit means for transmitting airunder pressure from an air supply and including means for directing theadditional air into the vicinity of said nozzle outlet means therebyenabling the additional air to mix with the mist exiting from saidnozzle outlet means which increases the available air to supporting mistdroplets and increases the volume of mist produced by said unit withoutincreasing the air turbulence within said unit so that said unit may bekept smaller in size;

an exit means for conducting the mist now mixed with additional air to amist receiving installation;

a collector disposed and supported in spaced opposed relationship tosaid outlet means from said nozzle, in order that the liquid dropletswhich are not suspended in air may strike said collector and condenseinto liquid form.

References Cited UNITED STATES PATENTS ALLEN N. KNOWLES, PrimaryExaminer M. Y. MAR, Assistant Examiner US. Cl. X.R.

